Supervisory signal system



Aug. l2, 1941. F. H. HANLEY ETAL SUPERVISORY SIGNAL SYSTEM Filed April19, 1940 Patented Aug. 12, 1941 UNITED STATA-ES PATENT r Vsurenviso'nvSIGNAL SYSTEM M Frank ,Harold lllanlefy,` Butler, and `rank-J. [,Car-

ter, 'Millburn, N. J., `Orville HowardjDavidsmeyer,` Downers l(grrove,'Il1.,` and Otha M Lamberson, FlushinggN. Y., assignors of JtwothirdstoAmericanTelephone and`f1elf'egraph` j Company, a corporation of NewYork, andone-r" w i third to Bell Telephone Laboratories, Incorpof lrated, a corporation of New York Appucanm AprilV i9, 1940, serialV Noj330,594 V12v claims. reina-v5) This invention relates to signalingsystems",l and moreHparticularly-to telegraph systems, including sc-ca'lled KSP circuits.` With greater par# ticularity," the` inventionrelates to"syfsteins"in which KSF circutsfare interconnected"I atgaswitching 'point for throughfoperation ,by means of. a twof-conductorcord circuit repeater, with the requirement, for efficient operation, ofcertain supervisory sgnaling'features.

KSP circuits, the letters indicating inter-cnice communication circuits-formerly 'jknown as communication `spare patch-ing i circuits.` @Insome Yin'stancesfit is found ythat between certain onices the number ofthev attendants communi` cations is'not large enough'tI justify` theprovision of direct KSPcircuits. According1y, it becomesnecessarii o r`desirablefto provide at cer--A tain pointslswitching arrangements by theuse of iwhichlconne'ctions can be f built up to handle the attendantscalls between` 't lfose`oices.

The desired 'switching is satisfactorily taken care' of'f throughthe'instrumentality of a twoconductor." cord circuit repeater provided atthe switching ollice:` `The use foi such a repeater, however,involves'problems of` supervisory'signalling between attendants. Moreparticularly,

there' must be provision for busy and disconneetr signals without unduefinterference with the4 communicationover the-KSPcircuitsf To meetsatisfactorily therequirement just L stated withf a single" indicatorrperrepeater appearance isv the principalobjec't'- cf the presentinvention'. Another `object ofjtheinventionisto provide for4 supervisory'signaling in association with a cord lcircuit repeater, which signalingwillb'e Vsat; isfactoryfin'fcases offopereltion at theswitc'hing ofliceone; multiple basisf Aj further' object of the invention is to providefor the supervisorysignaling indicated hereinbe# reasonablylecono'mical.

\ fore byv means of apparatus which is simpley and The inventionmay begenerallydescri the `co`mbination`- o'ffa cord vcircuit rep 'vsupervisory signal, indicating meanstfa mated` means for causrlg` the;signer means to junctionV ior the indication bus'yf for; time?) @fumoand t of afdiscon" tsign al ."f f-.Oiheri'obieg and, advaltaeszof .theinver; will beinade cle inthe folioifiijngdetailed e-,

s cription off 'onjef1 desirable,embodimenttlieren referencetheaccomwhich is toi-be ad ranyirigdrawina l It is deemed desirabletodescribe the invention in a form adapted togoperaticn on"a;`multiplebasis.. The I Inodiiications"v .ci this form ivvlfiiclfi leave the'epparatusledffirciliie .et fieri operation on a non-niultiple basisherwill'be obvious or will be pointed out. 1n the drawing?-` ff l j 5 gFig'ure 1 shows cliagrarnri'fiati-callyV 4and in'partschematically,thearrangement offthe cord circuit` repeater and thejdir'ectly'associated fappa ratus andcircuits forfpovidipg thefdefsiredyuipervisory signalsat'the repeater posit' Fig.v 2 shows diagrammaticallysuitable1 appa# `ratus directlyl associated with aV Ksljfcircuit tiple,`which apparatus functions in coperatiri with the apparatusshown in Fig.v1;I and; v Fig. 3` shows' diag'rar'nniatically-iandinrpart schematicjauysuitableapparatus 'at inventing? ofce' for transmitting the\disconnectvA sigan-al to the repeater point. f' "Withreference' te thedetailsotV the drawing and iirstl with particular ref erenceto" Fi "l",the apparatusv at the Iswitching oice "includes" a single line telegraphrepeater and rtelegraph lopf--terminalsf'li and Ta The repeater isterminated on en -'inward cord'and `anY outward cordl-"'Two appearancesoi the irepeater areshown, repref' sentativ'e of anysuitable numberof'niultiple *ap-- pearances, at positions t and2. The 'inward cord'terminations are on plugs P1 and P1, re'-V speetiveiyf; similany the'outward ecru terminates onplugs P2 andPz at tl'ietwoA positionsrespectively-. 'The 'signal iridicator'fat positi'oiir l takes theformof a'lamp L While-l-ainpl is provided at the' second positionf'Directlyas'sociatedwith each repeater positionfonthe board'is'afboardrelayiR' r'R "`with a plurality of armatures and contat's. 'It will beunderstoodthat if the' operation is on a non-"multiple basis,` onesetof` plugs', lamp and board relay'-foriexample, -P1I,"P2`,`f L and E-suilices and thevassociat'edconnecting circuits; are accordinglysimplified;r '1'Il1 remainingl apparatus 'of Fig.: f1 includes *a leakrelay R,

a transfer relay R2, a line relay Ra having a winding in circuit withthe inward cord, an alternating current relay R4, a delay relay R5 and asignal relay Rs, all with suitable connections and arrangements forvoltage supply, as will be more clearly understood from the followingdetailed description of the operation of the system as particularlyaffecting the apparatus of Fig. l.

It is assumed that the repeater and the KSP circuits are operated on amultiple basis.I yIf the repeater is in use by an attendant at anyposition, the attendants at all other positions are advised of this factby a repeater busy signal, as will be discussed more fully hereinafterthis indication is given by the lighting of lamp L or L associated withthe particular repeater appearance. If it is noted that the repeater isidle, the attendant who has to make afswitched KSP call makes with thetip of the outward cord a busy test of the KSP multiple. The apparatusprovided for this test will be fully disclosed hereinafter in connectionwith the discussion of Fig. 2 of the ,drawingsV ,It suii'ices to stateat this point that if .the tested KSP circuit is busy, the lamp willlight. Ifthe test indicates that the particular KSP circuit is idle, theplug of the outward cord is inserted `into the jack of the KSPmultiple.` By circuit arrangements which will be more fully disclosed inconnection with Fig. 2, battery is applied to the tip of the outwardcord and the circuit is completed through contact 4 of relay R2 and thewinding of the leak relay R1 to ground, this circuit constituting a leakcircuit on the tip of the cord. Relay R1 operates and by the closing .ofits upper armature and contact completes a circuit lfrom lbattery B1through resistances 6 and 6 and contacts vI and I of relays R and D',respectively, to the lamps L and L', it being understood `that lampscorresponding to any additional multiple appearances ofA the repeaterwill have their lament circuits similarly completed. The lightingy ofthe lamps thus produced gives a busy-indication at all appearances ofthe repeater; The operation of relay R1 also closesthe lower armatureand contact to apply ground'over that armature to the lower or secondarywindings of relays R and R and any other board relays which may be addedto correspond to additionalV multiple appearances. When the inward cordof the repeater is inserted by the attendant at one position into thejack of the calling KSP circuit, the upper or primary winding of theassociated board relaywhich for the purpose of illustration will betaken to be relay R corresponding to position I-is energized, the sourceof the energy being more fully discussed hereinafterl in connection withFig. 2. Relay R will now operate and by the action of the armature shownbelow the electromagnet in the drawing opens contact 'I, thusVextinguishing lampL Yat position I where the' connection is being made.By the upper contact of the armature now made, this lamp L is vconnectedto the armature of the signal relay Re and is thus placed in position toreceivea disconnect signal from the calling oiilce. When relay Roperates, the closing of contact 8 completes a locking circuit for therelay from battery B through-contact 8,

the lower winding of the relay and the lower contact and armature ofrelay R1 to ground over the last mentioned armature.

The closing of contact 9 upon the operation yoi relay R connects batteryB to ground through the winding of the .transfer relay R2. This transferrelay operates to open contact 4 and close contact I U, thustransferring the winding of the leak relay R1 from the tip of theoutward cord to the sleeve of that cord. This transfer operation placesthe leak relay in a position such that the relay does not interfere withthe transmission path and yet is maintained in operated condition.

It will be noted that with the connection completed through the repeaterat the switching ofce, lthe upper or line winding of the line relay R3Lis included in the inward cord circuit. As

4stated hereinbefore one of the objects of the invention is to lindicateby the signal indicator, l5'

such as lamp L, the reception of a disconnect signal from the connectedcalling oflice. It is, of course, necessary that there be satisfactorydiscrimination between the disconnect signal and any other signalstransmitted over the built-up circuit. As will be more fully consideredhereinafter in connection with Fig. 3 of the drawing, the distinctivesignal transmitted for disconnect purposes may take the form of a 20-cycle ringing current. vIt will be noted that relay R3 includes abiasing winding and has certain circuits `associated with the markingand spacing contacts of its armature. When the distinctive 20-cycleringing current comes in from the calling oice, the operation of relayR3 causes the alternate charging of condensers C1 and Cz through thelower or secondary winding of the alternating current relay R4 and thedischarging of these condensers through the upper or primary winding ofrelay R4. This relay is designed for slow release. Condensers C1 and C2form a part of the resonant circuit including the retard -coil II andthis resonant circuit is tuned very closelyto 20 cycles per second;accordingly, the condensers can be fully charged and discharged only ata rate which corresponds to or is very 'close to the resonant frequency.Resistances I2 and I3 and condensers I4 and I5 are provided for thepurpose of reducing sparking at the contacts of the line relay R3. Thealternating current relay R4 operates on the `charge and discharge ofcondensers C1 and C2 at the predetermined frequency, the marginalfeature of the relay preventing its operation when the interruptingfrequency of the signaling current differs from the predeterminedfrequency.

The delay relay R5, which is provided for the purpose of guardingagainst false operation of the signal receiving circuit on Morsesignals, for example, is made slow-releasing and is normally in operatedposition, the relay circuit being shown as extending from ground at I6through battery B2 and the relay winding to ground at I1. In thisposition of the relay, its contacts are open. When the alternatingcurrent relay R4 operates, ground at I8 is connected through thearmature of relay R4 to complete a circuit for the battery B2, and thusthe winding of relay R5 is short-circuited and that relay releases afterVa suitable interval. It will be noted that upon the release of relayR5, it is locked in the released position, the locking circuit extendingfrom ground at I6 through battery B2, the upper contact of relay R5 andthe lower-,contact of the leak relayr R1 to ground. 'Ihe closing of thelower contact of relay R5 upon its release completes a circuit throughbattery B3, that contact and the winding of the signal relay Rs to anysuitable device for interrupting the circuit thus completed at afrequency of 60 interruptions per minute, the interrupting device beingone well understood in the art and indicated on the draw-'-` ing as 60I. P. M. The signal'relay Rs'follows the 60 interruptions per minute andinter` mittently connects battery B4 through itsupper armature and theclosed contact 22 of board relay R to lamp L at the position where 'thethrough connection has been made. \The esultantv flashing of this lampindicates ythe reception of the disconnect signal from the calling KSPollice. It will be noted that theaarmature of relay R', whichisunoperated, rests on its lower contact 1', leaving contact 22 open,yand consequently there is no` disconnect signal circuit completedthrough the. lamp L. .Thus pron vision is made for the appearance ofthe` nashing disconnect signal at the 'repeater position where thethrough disconnection has been ,made and at no other appearance of therepeater.`

After the reception of the flashing disconnect signal the attendant`removes the inward and.

outward cords simultaneously and the leak relay R1 is released. Therelease of this` relay removes the ground on the locking circuit of theboard relay R (or any other board relaywhich may have been operated) andthis board relay is restored to,Y normal position, causing the releaseof the transfer relay R2. `As a result of the re-` leaseof relays R1, R`andRz, the repeater `busy lampsat all appearances'are extinguished andthe locking circuit iorfthe` delay relay R5 is opened, relay R5returning to its-,normal operated position. Consequently, the circuitthrough the winding of the signal relay Rc is opened and the disconnectsignal circuitithusbroken.` 1 v- It will be noted `on Fig.` 1 ofthedrawing that the signal `relay Re may be provided `with a'second (lower)armature and contact for the purpose of controlling an auxiliary signalcircuit if such is desired. y -f When the repeater is provided at oliceshaving a KSP circuit multiple, there mustl be cirT cuit arrangements atthe repeater` position whereby it may bel ascertained by .the attendantwhether or not a desired KSP circuit is busy. A satisfactoryarrangementis one-in accordance with` which `eachKSP circuit is equipped with arelay and other apparatus ior placing the sleeve of each multiple jackat Zero potential if the circuit is idle andat some potentialsuch as l65voltsiiythe circuit is,busy.v` I t is desirable that thisuprovision bemade `without interference with the transmissionpaths of they circuit,which also utilize Vthesleeves of the jacks The arrangement forproducing the non-voltage and voltage condition ofthe jack sleeves, usedin conjunction with'the `tiptest circuit on the outward cord of therepeaten-.is shown in adequate detail in Fig. 2-of the drawing.`Thisvdisclosure includes an Vindication ofthe `KSP multiple with aninitial appearance fandfa final appearance, relays Re Vand Rv` andsuitablelresistances and sources of potential, as will now be `describedin further detail. y

With no' connection `festalclishedto kthe KSP circuit multiple,azcircuit is completed from ground through battery B5, the right-hand orprimary winding ot relay Rs and the `auxiliary contacts [Band llll `ofthe KSP vmultiple jacks to ground.` In this. condition-the shunt acrossresistanceswZl. between Ytilearrriature of relayRs n and thel contact`of that relay isopenV and-,the sleeves of all "of the jacks of theKSB/circuit multiple are inthe electrical center of the `KSP loopcircuit. This condition has the result that there is no potentialtouground on the sleevesof the -jacks associated with the KSP multiple..If an attendant makes a tip busy test with the outward cord oftherepeater by touching the tip to the sleeve of the KSP multiple, novoltage is applied to the test circuit and the leak relay R1 (Fig. l)does not operate `to light the signal lamps. lfynow, an incoming KSPsignal is received:thenperating circuit of relay R7, which is completedthrough contactsZU and 20 of the KSP` multiple circuit, `if opened,relay R1 re* leases andbattery Bsris connected through therelay"armature` in a circuit including the lefthand or secondary windingof relay Rs, this latter circuit being completed.v over the auxiliarycontacts I9 and I9 to ground. f VThe current thus caused to flow throughthesecondary winding of relay R8 is `equal and opposite in direction tothe current of the primary winding and, as alresult, relay Rs isreleased to close its contact. The closing of the "contact of this'relay applies a shunt to resistances 2| and, consequently, the sleeveof` the KSP multiple is placed otherwise than at the electrical centerof the circuit; in the specic disclosure of the drawing there will beapplied to the sleeve a potential amounting to about volts to ground.If, under this condition, the tip `oflthe outward cord of the repeateris touched to the sleeve of the called KSP circuit, this potential of 65volts causes a current to now through the winding of the leak relay 'Ri(Fig: l) :to ground,` theresult being the operation of the leak` relayand they connection of `battery B1 to the lamps L and L'. When a plug isinserted 4in the KS-P multiple, the `auxiliary contactnl!! or I9 isopened and relay Rs is released. i f i l l If an `attendant at onerepeater' position has established a connection `by .plugging in at oneappearance of a certain KSP circuit in the KS-P circuit multiple,` and:another attendant desires to vbuild up `a connection-over that circuit,the tip ltest'will` produce abusy indication since the establishedconnection will have resulted in the opening of either Contact I9 orcontact |9,\the removal of the ground from the right-hand winding ofrelay Ra andthe closing of the shunt aroundl resistances `2 I .Y

It will be `observed ythat the 13D-volt circuit shown in Fig. 2``notonly provides the holding current for relay R7 but also furnishesthe potential for the operation of the leakrelay R1 of Fig. 1under'appropriate conditions.

As `,has beeny indicated hereinbefore, in order that there may beAadequate discrimination at the switching oilice'between` a disconnectsignal and Morse signals, for example, a distinctive signalmust be sentfrom the calling oilice connected ina built-up KSP circuit. The diagramof Fig. 3 indicatesra suitablel arrangementwhich may be providedior thispurpose at an-office which will -be regarded "as a -calling office. When*this ofce .has completed the communication over,` the built-up KSPcircuit, the nonlocking ,key K associated with the telegraph test set isoperated for ,approximately two seconds. This` operation applies1Z0-cycle ringing current-through the Asounderlofthe telegraph set tothe tip of plug P, which* terminates the cord, and on Yover .thetelegraph `circuit tothe KSP repeater point, The transmission of the20cycle ringing current through the sounder of the telegraph set isnecessary inorder that theattendant at the calling oflicemay'be assuredthat the disconnect signal-has been transmitted. `As has been describedinsomedetail in connection with Fig. 1, the'receptionr at the KSPrepeater oiiice of this distinctive disconnect signal is indicated bythe flashing of the signal lamp at the repeater position through whichthe connection is made.

While the invention has been disclosed speciiically as applied to KSPcircuits used in certain telegraph systems, it will be understood thatit may be applied to other communication systems. Likewise, it will beunderstood that many changes from the specific arrangement shown may bemade vwithin the scope of the appended claims.

What is claimed is:

1. In a signaling system including a plurality of oflices and aplurality of direct point-to-point circuits interconnecting certain ofsaid oiiices, a cord cir-cuit repeater at one oflice for connecting two"of said direct circuits for through operation between two other offices,`a signal indicator associated with said repeater, and means associatedwith said'indicator for indicating lthereby whether a certain directcircuit is in use and the reception of a distinctive signal from thecalling office.

2. In a signaling system including a plurality of oiiices `and aplurality of direct point-to-point circuits interconnecting certain ofsaid oiiices, a cord circuit repeater at one office for connecting twoof said direct circuits for through operation between two other oices,said repeater and said direct circuits being adapted for operation on amultiple basis, said repeater having at each of its appearances asignalindi-cator, and means associated with said indicator for indicatingthereby whether the repeater is in use at another position, whether acertain direct circuit is in use, andthe reception of a disconnectsignal from the connected calling cnice.

3;' In Va signaling system including a plurality of oilices and aplurality of direct point-to-point circuits interconnecting certain ofsaid oiiices, a two-conductor cord circuit repeater at one oiiice forconnecting two of said direct circuits for through operation between twoother oflices, a signal indicator associated with said repeater, andcircuit means associated with said indicator for indicating thereby theidle or busy condition of a certain direct circuit and the reception ofa distinctive signal from the connected calling oiiice.

4. In a signaling system, including a plurality of oflices and aplurality of direct point-to-point circuits interconnecting certain ofsaid oiiices, a two-conductor cord circuit repeater at one oflice forconnecting two of said direct circuitsfor f through operation betweentwo other offices, said repeater and said direct circuits being arrangedfor operation on a multiple basis, a signal indicator associated withsaid repeater at each of its appearances, and circuit means associatedwith said indicator and indicating thereby the use of the repeater atanother position, the idle or busy condition of a certain direct circuitand the reception of a distinctive disconnect signal from theconnectedcalling oflice.

5; In a signaling system including a plurality of offices and aplurality of direct point-to-point .circuits interconnecting certain ofsaid oices, a cord circuit repeater at one oice for connecting two ofsaid directl circuits for through operation between two other ofiices,said repeater having an inward cord, an outward cord and a single signalindicator, means associated with said indicator for indicating therebywhether a certain one of said direct circuits is in use, and meansassociated with said indicator and operable when a connection has beenestablished for indicating by said indicator the reception of adisconnect signal from the connected calling oflice, said last statedmeans being responsive only to current of certain distinctivecharacteristics..

6. In a signaling system including a plurality of oliices and aplurality of' direct point-to-point circuits interconnecting certain ofsaid offices, a cord circuit repeater at one oiice for connecting two ofsaid direct circuits for through operation between two other oices, saidrepeater and said direct circuits being arranged for operation on amultiple basis, saidrepeater having an'inward cord and an outward cordeach adapted for switching operations at each appearance of therepeater, a signal indicator associated with each multiple appearance ofthe repeater, means associated with said indicator for indicatingthereby whether the repeater is in use at another position, meansassociated with said indicator for indicating thereby whether a certainone of said direct circuits is in use, and means associated with saidindicator and operable when a connection has been established at thecorresponding position of the repeater for indicating by said indicatorthe reception of a disconnect signal from the connected calling oiiice,said last stated means being responsive only to current of certaindistinctive characteristics.

7. In a signaling system including a plurality of oi'ces and a pluralityof direct point-to-point circuits interconnecting certain of saidoiiices, a cord circuit repeater at one oflice for connecting two ofsaid direct circuits for through operation between two other ol'lices, asignal indicator associated with said repeater, means for sending tosaid repeater from a distant calling office connected therethrough adistinctive supervisory signal, means associated with said repeater andresponsive only to the reception of said supervisory signal forproducing a distinctive operation of said indicator, and means forindicating by said indicator the idle or busy condition of a certain oneof said direct circuits.

8. In a signaling system including a plurality of offices and aplurality of direct point-topoint circuits interconnecting certain ofsaid oices, a cord circuit repeater at one office for connecting two ofsaid direct circuits for through operation between two other offices,said repeater and said direct circuits being arranged for operation on amultiple basis, a signal lamp associated with each appearance of saidrepeater, means for sending to said repeater from a distant calling oiceconnected therethrough current of distinctive characteristics, meansincluding a chain of relays associated with said repeater for causingsaid lamp to flash in response to the reception of said distinctivecurrent, and means for causing said lamp to indicate the use of therepeater at another position and the idle or busy condition of a certainone of said direct circuits.

9. In a signaling system including a plurality of oices and a pluralityof direct point-to-point circuits interconnecting certain of said olces,a cord circuit repeater at one ofce for connecting two of said directcircuits for through operation between two other offices, said repeaterincluding an inward cord, an outward cord and a signal lamp, a directcircuit multiple associated with said direct circuits and said repeater,means responsive to the touching of the tip of said outward cord to ajack sleeve of the direct circuit multiple associated with a busy directcircuit for lighting said lamp, and means operable when a connection hasbeen established through said repeater for` ashing said lamp in responseto the reception of a disconnect signal from the connected callingoflice, said last stated means being responsive only to current ofcertain distinctive characteristics.

10. In a signaling system including a plurality of oices and a pluralityof direct point-to-point circuits interconnecting certain of saidoi`ces, a cord circuit repeater at one -oilice for connecting two ofsaid direct circuits for through operation between two other offices,said repeater including an inward cord and an outward cord and beingadapted for operation on a multiple basis, a signal lamp associated witheach appearance of the repeater, a direct circuit multiple associatedwith said direct circuits and said repeater, means for lighting saidlamp when the repeater is in use at another position, means responsiveto the touching of the tip of said outward cord to a jack sleeve of thedirect circuit multiple associated with a busy direct circuit forlighting said lamp, and means operable when a connection has beenestablished through said repeater at one of its positions for ashing thelamp at that position in response to the reception of a disconnectsignal from the connected calling oilice, said last stated means beingresponsive only to current of certain distinctive characteristics.

11. In a signaling system, including a plurality of offices and aplurality of direct pointto-point circuits interconnecting certain ofsaid offices, a cord circuit repeater at one office for connecting twoof said direct circuits for through operation between two other offices,said repeater including an inward cord and an outward cord, a signallamp associated with the repeater, a direct circuit multiple at saidoffice including a plurality of jacks, means associated with saidmultiple for impressing a voltage on the sleeves of the jackscorresponding to a certain direct circuit when said circuit is in useand for removing the voltage when the circuit is idle, and circuit andswitching arrangements associated with said repeater and said lampwhereby the lamp will give a plurality of indications, said arrangementsincluding means responsive to the touching of the tip of said outwardcord to a multiple jack sleeve when a voltage is impressed thereon forlighting said signal lamp, means responsive to the connection of theoutward cord with said direct circuit multiple for lighting the lamp,means responsive to the completion of a connection through the repeaterfor extinguishing the lamp and preparing the same for the reception of adisconnect signal from the connected calling ofce and means responsiveonly to current of certain distinctive characteristics transmitted fromsaid calling ofiice for causing the dashing of said lamp as a disconnectsignal.

12.111 a signaling system including a plurality of oiiices and aplurality of direct pointto-point circuits intercononecting certain ofsaid oices, a cord circuit repeater at one ofli'ce for connecting two ofsaid direct circuits for through operation between two other oi'lices,said repeater including an inward cord and an outwardl cord and beingdesigned for operation on a multiple basis, a signal lamp associatedwith'each appearance of the repeater, a direct circuit multiple at saidoffice including a plurality of jacks, means associated with saidmultiple for impressing a voltage on the sleeves of the jackscorreponding to a certain direct circuit when said circuit is in use andfor removing the voltage when the circuit is idle, and circuit andswitching arrangements -associated with said repeater and said lampswhereby the lamps will each give a plurality of indications, saidarrangements including means responsive to the touching of a tip of theoutward cord to a multiple jack sleeve when a voltage is impressedthereon for lighting said signal lamps, means responsive to theconnection of the outward cord with said direct circuit multiple forlighting the lamps at all repeater positions, means responsive to thecompletion of a connection through the repeater at one position forextinguishing the lamp at that position and preparing the same for thereception of a disconnect signal from the connected calling oflice, andmeans responsive only to current of certain distinctive characteristicstransmitted from said calling oice for causing the ashing of said lampas a disconnect signal.

FRANK HAROLD HANLEY.

FRANK J. CARTER.

ORVILLE HOWARD DAVIDSMEYER.

OTI-IA M. LAMBERSON.

